CENTURY'S LAST PARTIAL SOLAR ECLIPSE ON TAP MAY 10

The last annular solar eclipse that will be visible in the Cape Girardeau area this century will occur May 10.

If you miss this one, the next annular eclipse of the sun won't occur again in the Cape area until at least 2012, according to Craig Joseph, an astronomer and professor of physics at Southeast Missouri State University.

Joseph said, "The annular solar eclipse will begin in Cape Girardeau at about 10:14 a.m. It will peak at about 11:53 a.m., when about 94 percent of the sun will be covered or eclipsed by the moon."

A solar eclipse is an area of darkness, or in this case, reduced sunlight, that travels across the Earth's surface in a relatively narrow path during the daytime.

The center of the path of the May 10 solar eclipse will enter the United States at the Texas-Arizona border, move northeastward over central Oklahoma, extreme southeast Kansas, southwest, central and northeast Missouri, central Illinois, northern Indiana, a part of western Pennsylvania, northern New York, and southern Maine, before passing over the Atlantic Ocean.

Joseph said residents who live in the metro St. Louis area will see a darkened solar disc with a bright ring of sunlight surrounding it. Those living north or south of St. Louis will see a partial covering of the sun and no ring.

Joseph said a solar eclipse happens when the moon comes between the Earth and the Sun and the Moon's shadow travels across the surface of the Earth. There are two types of eclipses: total and annular.

Joseph said the Moon's shadow consists of two parts: a dark umbra and lighter penumbra. The umbra gets smaller the further away the Moon.

When the umbra reaches the surface of the Earth, a total eclipse of the sun is visible. The width of the shadow usually is less than a hundred miles wide, but may travel several thousand miles across the Earth.

Outside the path of the umbra a partial eclipse will be visible. The closer one is to the umbra, the greater the percentage of the sun will be covered. In this case, a partial eclipse of the sun can be seen over an area thousands of miles wide.

An annular eclipse of the sun occurs when the Moon's umbra doesn't reach the surface of the earth, but seems to "hang" in space. When the umbra passes overhead, you will only see the darkened solar disc with the ring of light (or annular) surrounding it.

"Contrary to what many people believe, the sky does not darken during an annular eclipse," said Joseph. "In fact, if no one told you that an eclipse was occurring, you might not even be aware of it. If there are no clouds, you should notice the sky turning a deep blue.

"Because it will occur around noon, there should be a noticeable drop in the temperature at the peak of the eclipse."

Joseph said that if the sky is clear, telescopes with special filters will be set up in the courtyard area in front of the three science buildings on the university campus.

Joseph said those who plan to view the solar eclipse should never look directly at the sun without a protective filter, even at the peak of the eclipse.

He said one way to view the eclipse is to focus a pair of binoculars on a white piece of paper with the other end aimed at the sun. "You'll see two images of the partially covered solar disc on the white paper," he said.

Joseph said another safe method of viewing the solar eclipse to expose a roll of 35mm black and white film to daylight for about 30 seconds. He said, "Just pull the film out of the canister so it is exposed, then develop the film. You will have a dense black negative. Cut the film into two sections and put the two pieces of negative together.

"You will be able to look directly at the sun for about 30 seconds at a time. Wait about 2-3 minutes before you look at it again."